cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A343278 a(n) = Stirling2(n, ceiling(n/2)).

Original entry on oeis.org

1, 1, 1, 3, 7, 25, 90, 350, 1701, 6951, 42525, 179487, 1323652, 5715424, 49329280, 216627840, 2141764053, 9528822303, 106175395755, 477297033785, 5917584964655, 26826851689001, 366282500870286, 1672162773483930, 24930204590758260, 114485073343744260
Offset: 0

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Author

Peter Luschny, Apr 20 2021

Keywords

Comments

Number of partitions of an n-set into ceiling(n/2) nonempty subsets.

Crossrefs

Bisection gives A007820 (even part),
Cf. A048993, A129506, A343279.

Programs

  • Mathematica
    Table[StirlingS2[n, Ceiling[n/2]], {n, 0, 25}] (* Amiram Eldar, Apr 20 2021 *)
  • PARI
    a(n) = stirling(n, ceil(n/2), 2); \\ Michel Marcus, Apr 20 2021
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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